The present invention relates to the chemical treatment of wells that are in a state of production. In one aspect, the present invention relates to use of a pump that mixes the desired treatment chemicals with sufficient volume of flush from the well to carry the chemicals to the downhole equipment.
Producing wells commonly have pumps and other equipment inside and towards the bottom of the well. This equipment is subject to corrosion, and chemicals are used to protect this downhole equipment. One common method of treating downhole equipment is by using xe2x80x9ctreater trucksxe2x80x9d that travel from well to well to deliver the chemicals. Valving at the well site is changed and the treater truck recycles flush from the well through the well while adding chemicals into this recycling flush. When the treater truck is finished, the valving is changed back to its production position. The use of treater trucks is expensive. Additionally, they are unreliable as weather, unreliability of the operator, equipment malfunctions, etc. may disrupt the planned schedule for well treatment. Also, treater trucks are heavy and can damage the land owner""s roads and property. There is also a safety risk with the human treater truck operators handling valves at the well site which if not handled properly could damage equipment. Relying on treater trucks is also disadvantageous because there are no chemicals treating the well in between the treater truck visits.
Another method of treating wells is using a chemical pump that is permanently at the well site injecting chemicals into the well casing. While this pump can continuously provide the chemicals, the volume of chemicals is very low. Whereas the treater trucks mixed the chemicals with the large volume of recycling flush from the well, the stand alone chemical pumps are typically small positive displacement pumps that inject small quantities of chemicals that may just xe2x80x9cfloatxe2x80x9d near the top of the well without traveling to the bottom of the well in sufficient quantities to treat the downhole equipment.
U.S. Pat. No. 4,375,833 to Meadows discloses the use of valving that is electronically changed periodically to recycle the flush from the well as the treater truck method does. Upon change to the recycling position, chemicals are injected into the recycling flush. The drawbacks of this method is that once again the chemicals are only treating the well periodically. Additionally, during recycling, the production of the well is off line. The valving and controls for this system are expensive and require maintenance. The Meadows patents also discloses the use of a rod pump that is used to deliver chemicals into the well either like discussed above or in combination with the valving disclosed in the Meadows patent. For example, during recycling, the rod pump delivers chemicals into to recycling flush.
A need exists for a device and method for low cost, low maintenance delivery of chemicals that will effectively treat the well.
The present invention provides a method of introducing chemicals by a method for delivering treatment chemicals into a well by siphoning off a volume of flush from a production line of a well with a flush pump while the well remains in production and introducing treatment chemicals to the suction side of the flush pump to be combined with the flush. The combination of the treatment chemicals and flush is then discharged into the well by the flush pump. Another aspect of the present invention provides a flush pump for carrying out this method. Further aspects of the present invention combine the operation of a chemical pump on concert with the flush pump.